There have been considerable problems associated with opening extended shelf life packaging containers configured with a gable top. Extended shelf life packaging containers are containers which give perishable food products, such as juices or milk, a longer shelf life, up to periods of 6 months in some cases. The laminated structure used for construction of extended shelf life packaging, generally has as a main structural support member made of a cardboard or paperboard. Disposed on the side of the paperboad, which will ultimately be the outside of the constructed container, is one or a plurality of thermoplastic layers constructed of low density polyethylene or high density polyethylene or combinations thereof. Disposed on the side of the paperboard, which will ultimately be the inside of the constructed extended shelf life packaging container, are a foil barrier layer and a plurality of thermoplastic layers, again being constructed of material such as low density polyethylene or high density polyethylene or combinations thereof.
One of the significant problems to be solved in the use extended shelf life packaging was to provide a high integrity seal for the container while also maintaining ease in opening the container. Conventional sealing of extended shelf life packaging utilized various placements of abhesive coating material in the area of the gable top enclosing the pouring spout. Without such use of abhesive coating applications on the gable top, there was great difficulty in opening the gable top of the container, since, as stated, high integrity sealing is a must in extended shelf life packaging, often tearing or ripping of the pouring spout resulted. The use of abhesive coating for traditional foil lined containers was set forth in an U.S. Pat. No. 3,334,799. The improvements to such dispositions of abhesive coating are found in patent application Ser. No. 596,517 of Catarella et al. assigned to International Paper Company.
Even though there is placement of abhesive coating on the containers to facilitate extending pouring spout, there remains the problem that the seal containing the abhesive coating material is not as strong as a seal not requiring the use of any abhesive coating.
In the past, there has not been any specific attempts to construct a gable top for an extended shelf life packaging container, which has a high integrity at the laminer rib seal which does not house portions of the pouring spout within the seal. As previously stated, extended shelf life packaging to date has utilized the positioning of abhesive coating material in the seal area of the container to allow ease in opening the container. In the past there have been various attempts to provide different methods for opening gable tops which do not utilize portions of the laminar rib to define part of the pour spout opening. However, these gable top structures were not constructed of a laminated structure such as is used in extended shelf life packaging containers. Therefore, such configurations would not be particularly useful for present day extended shelf life packaging containers for defining the pouring spout area.
In the past, gable top structures of conventional thermoplastic coated paperboard utilized weakened lines of severance of slits through the thicknesses of the structure material to attempt to facilitate the opening of a pour spout without worry of providing abhesive coating to the laminated rib disposed at the top of the gable top. In order to insure that there was not a leakage problem and to facilitate opening the package, in some cases, a strip of tape was heat sealed to the line of severance or slit on the outside surface to facilitate opening the container. It was also important that no score lines extend to the weakened line of severance, since it created leakage problems due to the capillary action of the fluid in the container in the score line to the weakened line of severance, thereby causing leakage of the fluid into the structure itself. When it was desired to open these packages having weakened lines of severance covered by tape, the tape was pulled away, thus removing the immediate layer of thermoplastic and a portion of the fibrous paperboard material from the panel. This provided a weakened area adjacent to the weakened line of severance to facilitate opening the container. Patents disclosing the use of tape on conventional thermoplastic coated paperboard containers are U.S. Pat. Nos. 3,570,744; 3,561,665; 3,554,430; 3,537,634; 3,452,919; 3,450,328; 3,355,083; 3,348,755; 3,295,739; and 3,186,621. Patents disclosing the use of weakened lines of severance that are sealed within the laminar rib of the gable top of the conventional containers are U.S. Pat. Nos. 3,543,993; 3,245,603; 3,178,091; 3,178,089; and 3,167,231. A patent which discloses the use of flap, which is folded over and heat sealed within the laminar rib for covering a weakened line of severance in a portion of the laminar rib is U.S. Pat. No. 4,390,121.
The present invention overcomes these problems by providing a pouring spout opening configuration utilizing weakened lines of severance for extended shelf life packaging containers, which is superior to conventional configurations.